U.S. 2006/0 086 923 discloses a valve assembly including a first gate having at least one opening and a second gate having at least one opening, the second gate being spaced from the first gate. The valve assembly has first and second discs disposed between the first and second gates, each disc having at least one opening. The assembly also includes a biasing element disposed between the first and second discs for normally urging the discs away from one another and toward opposing inner faces of the first and second gates. The first and second discs are rotatable. The valve assembly is in an open position when the openings of the rotatable discs are in alignment with the openings in the stationary gates. Turning the rotatable discs such that the openings in the rotatable discs are not in alignment with the openings of the stationary gates makes the valve assembly to adopt a closed position, so that no fluid is allowed to flow therethrough. The rotatable disc is provided with a surrounding gear ring and the valve assembly further comprises a worm drive. The outer surface of the gear ring includes teeth that engage with threads on the worm drive. In operation, as the worm drive rotates about its longitudinal axis, the threads engage with the gear teeth on the outer surface of the ring gear for rotating the ring gear. As the ring gear rotates, the rotatable discs rotate simultaneously therewith. The worm drive is operated by a motor for moving the valve between open and closed positions.
U.S. Pat. No. 5,127,438 discloses a faucet comprising three ceramic discs inside a housing. The first and the third disc are stationary and the second disc is rotatable by a stem forming a handle and located between the first and the third disc. The ceramic discs comprise holes such that when the holes are aligned, the faucet is open, and turning the rotatable ceramic disc turns the holes to be misaligned in successive ceramic discs which prevents water flow through the faucet. The housing is formed by a female housing and a male housing, such that the female housing is positioned on the male housing. A slot is provided through the female housing and the male housing, which slot forms a handle window. The stem forming the handle extends through the window. The first and third ceramic discs are axially movable by outwardly extending ears which extend into vertical grooves inside a side wall of the housing. The stem is attached to a pan and the rotatable ceramic disc is seated in the pan. The rotatable ceramic disc has ears extending outwardly from its side wall and the pan comprises axial grooves, whereby the axial movement of the rotatable disc is also permitted.